1. Field
This disclosure relates to a polymer and a composition and a film comprising the same.
2. Description of the Related Art
As information technology advances and becomes more widely used, there is an increasing need for an ultralight flexible thin display that consumes a low amount of electrical power and can be used to visualize and deliver information. In a flexible display, the flexible substrate generally determines performance, reliability, and price of the display. Common substrates include plastic substrates, which typically are light and easy to work with in a continuous process.
Currently available plastic substrates suffer from some disadvantages, however, such as low thermal stability. For example, a common polyimide film may be easily discolored to yellow or brown due to heat degradation as a result of a severe thermal history or simply due to the polymer structure. Such discoloration is typically due to formation of a charge-transfer (CT) complex inside a polymer molecule of an electron-giving part, in which a nitrogen atom centers inside the polymer, and an electron-receiving part, in which a carbonyl group centers inside the polymer, and also to the formation of a CT complex between polymer molecules.
To satisfy the increasing need for flexible substrates, plastics with improved properties, such as a lower coefficient of thermal expansion (“CTE”) and higher light transmission, are required. Accordingly, there is a need in the art for a polyimide polymer that exhibits improved thermal and optical transmission properties.